What is the role of Java Runtime Environment (JRE) when running Java applications?

Java Runtime Environment (JRE) is the runtime environment necessary for running Java applications. It includes:

• Java Virtual Machine (JVM) — a virtual machine that interprets Java bytecode and executes it on a specific platform.
• Java class libraries — a set of standard classes and APIs used by the application.
• Runtime support tools — such as class loaders, memory management (garbage collector).

When you run a Java application, the JRE ensures code portability and execution without the need to compile for a specific operating system.

Example of running an application:

java -jar myapp.jar

Here, the JRE launches the JVM, which executes the bytecode from myapp.jar.